An automatic vending machine is generally provided in the inside of a front door with a sample room for exhibiting the samples of articles of trade, the sample room being covered by a transparent window panel fitted in the front door. The sample room is provided on the rear wall thereof with a display plate on which a graphic display is printed. The graphic display is selected from such pictures and advertising words that are suitable for exciting consumers' interest.
Known display apparatus for an automatic vending machine have a single graphic display printed on a display plate, which is removably attached to the rear wall of the display apparatus to be exchangeable for another display plate, as disclosed in, for instance, Japanese Utility Model Publication Nos. A-55778/86, A-33174/86, and A-37578/86.
However, although these known display apparatus can be manufactured at low cost, when the graphic display is to be exchanged for another, doing so is troublesome, and it is actually hard to frequently carry out exchanging work.
To eliminate such a disadvantage, U.S. Pat. No. 2,680,316 suggests an apparatus comprising a plurality of vertically elongate display rods of the same size, each having a triangular cross-section, which rods are arranged side by side at desired intervals to be rotatable about their own vertical axes so that three side faces of the display rods can cooperate with each other to intermittently produce associated three different composite display figures when the display rods rotate together at the same time for every 120 degrees to have relevant side faces of the display rods aligned in a plane.
The display rod is usually made of plastics or aluminum, and the figures on the side faces of each display rod are formed by silk screen printing. Upon printing, relevant side faces of the rods must be positioned to be aligned with each other in completely the same level to be capable of forming a composite figure as a whole. For this purpose, a special device must be used to hold all the relevant side faces of the triangular rods collectively in the same level. Thus, it is hard to carry out the printing operation.
Furthermore, the distance of a space between the samples of articles of trade and the display rods is to be reduced because of the thickness of the triangular rod. Therefore, if the above-mentioned distance is to be increased to have a desired dimension, the depth of the body of the slot machine will also be increased. Also, if only a composite figure formed on an aligned surface consisting of the relevant side faces of the rods is to be exchanged with another, all the rods must be removed from the slot machine.